19994581 has 2 divisors, whose sum is σ = 19994582. Its totient is φ = 19994580.

The previous prime is 19994561. The next prime is 19994587. The reversal of 19994581 is 18549991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18576100 + 1418481 = 4310^2 + 1191^2 .

It is a cyclic number.

It is not a de Polignac number, because 19994581 - 2⁵ = 19994549 is a prime.

It is a super-2 number, since 2×19994581² = 799566538731122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19994587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9997290 + 9997291.

It is an arithmetic number, because the mean of its divisors is an integer number (9997291).

Almost surely, 2^19994581 is an apocalyptic number.

It is an amenable number.

19994581 is a deficient number, since it is larger than the sum of its proper divisors (1).

19994581 is an equidigital number, since it uses as much as digits as its factorization.

19994581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 46.

The square root of 19994581 is about 4471.5300513359. The cubic root of 19994581 is about 271.4172437299.

The spelling of 19994581 in words is "nineteen million, nine hundred ninety-four thousand, five hundred eighty-one".